<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button class="begin">开启</button>
    <button class="stop">停止</button>

    <script>
        var begin = document.querySelector('.begin');
        var stop = document.querySelector('.stop');
        var interval = null; // 全局变量，null是一个空对象
        begin.addEventListener('click', function(){
            interval = setInterval(function() {
                console.log('BOOM');
            },1000)
        })

        stop.addEventListener('click', function(){
            clearInterval(interval);
        })
    </script>
</body>
</html>